Einstein's Theory Passes Strict New Test

FiReaNGeL writes with an excerpt from a story at e! Science News: "Taking advantage of a unique cosmic configuration, astronomers have measured an effect predicted by Albert Einstein's theory of General Relativity in the extremely strong gravity of a pair of superdense neutron stars. Essentially, the famed physicist's 93-year-old theory passed yet another test. Scientists at McGill University used the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) to do a four-year study of a double-star system unlike any other known in the Universe. The system is a pair of neutron stars, both of which are seen as pulsars that emit lighthouse-like beams of radio waves."

And that, boys and girls,

...is the value of good old-fashioned study.

Re:And that, boys and girls,

It's the value of good old fashioned visual thinking and geometry actually, einstein's theories were so powerful correct BECAUSE he was an excellent visual thinker and thought in terms of geometry. Geometry is highly under-rated in mathematics and physics in my opinion.

Re:And that, boys and girls,

How is geometry underrated? Calculus starts with the study of low dimensional curves. Linear algebra is the study of simple geometrical transformations (rotations, translations, dilations) in high dimensional geometry. Functional analysis is basically the study of infinite dimensional flat geometry. Partial differential equations are implicit equations for small patches of curves and surfaces. That's about half the usual curriculum in undergraduate mathematics, and I haven't even mentioned differential geometry (generalized theory of curves and curved spaces) and algebraic geometry (generalized study of the properties of curves defined by polynomial equations).

Re:Can't be right

I hate it when people discuss science in this banal way. It is as if they think that the physical theories are what cause nature to act (the Laws of Nature). This is wrong. These physical theories only describe how nature appears to act. Quantum mechanics is a classic example. Look at all the different formulations that describe how the state vector or wave function or whatever you want to call it acts (Heisenberg's, Schrödinger's, Dirac's, Feynman's, etc.). They are all good theories because they explain the experimental evidence, they are simple, and they can predict things. Take a look at the so-called wave-particle duality. A photon, for example, doesn't act as a wave or as a particle. It acts as a photon (paraphrasing Feynman). We only describe it as acting as a wave or a particle.

The truth about science is that it may very well not be possible to understand why the Universe acts as it does. It may not even be possible to understand the most basic laws governing it. But we can certainly study and try to understand its behavior where we can observe it. General relativity does that well, and quantum mechanics does that well. Calling one right and the other wrong sort of loses its meaning in this context when both theories describe their data exceptionally well for the ranges that they observe. Neither of them proposes to govern nature, nor should we ever expect that of a physical theory.

Re:Can't be right

Feynman's take was that light is *always* particles. He was unequivocal about that.

Re:Can't be right

You are exactly right, but to paraphrase:

"All models are wrong, but some are useful." [wikiquote.org]

Re:Can't be right

Except that isn't possible, because theories that hold up well at describing things like gravity on a large scale break down horribly at the quantum level. Even basic interactions between particles cannot be described in the sense of, say, a truck hitting a telephone pole.

person A: "one day, man will fly"

person B: "Except that isn't possible, because man was not born with wings!"

Re:Can't be right

You are aware that "impossible" means "cannot be done" and not just "we can't do it right now", right?

Re:Can't be right

Calling one right and the other wrong sort of loses its meaning in this context

      I agree. Once again science... REAL science, is never about "right" or "wrong". It's about "can I use what you just told me in a predictable manner?". If it's BS and it doesn't work, then leave me alone I have stuff to do. :)

Re:And that, boys and girls,

You do realize that is what they're doing, right? They're looking out into the Universe for ways to test the theory against real live data.

Re:And that, boys and girls,

I think what he's saying is that since these scientists's job to to disprove relativity, or kill cancer, or cure AIDS, and they failed at their job, then they should not get their paycheck next month.

Seems perfectly logical to me.

Re:And that, boys and girls,

Yes, this upholds the theory that pink unicorns, which are known to exist, are invisible, otherwise this experiment would have revealed them. Further proof of the existence of invisible pink unicorns!!!

Here's an experiment you can do yourself. Find a dark room, such as a bathroom stuck between two other rooms and therefore windowless. Close the door and keep the light off. Reach out your hand. Do you feel anything? Holy Crap, you just found an OMGPONIES! Turn the light on, quick! Did you see the OMGPONIES!? No, you didn't. Further proof that OMGPONIES!s, known to exist, hate artificial lighting, and run very fast. Isn't that amazing?

Einstein: Really Smart

Usually pop culture gets these people's character pretty wrong. Elvis, for example, is "the King", when he was just a singing truck driver.

But Einstein they got pretty right. Sure, he didn't know everything, was smart really only within his very narrow discipline of mathematical theoretical physics. Einstein himself used to say "I really only ever had 4 good ideas, and 2 were wrong". But the couple he was right about, he was really right.

And with the wild hair, the pacifism, the "same suit every day so I don't have to waste time thinking about it", and the snappy short equations that explain everything, he's probably the coolest smart guy since they all used to wear togas and live on wine and souvlaki on the beach.

Re:Einstein: Really Smart

Einstein dabbled a bit outside theoretical physics. For example he had a patent [wikipedia.org] for a refrigerator design.

Strict new test? Psh!

If they want to REALLY test a theory, they should just post it on slashdot. You know, because mass opinion is what really matters, regardless as to what's right and wrong.

Re:Strict new test? Psh!

If they want to REALLY test a theory, they should just post it on slashdot.

      No, silly, that's just how you test the server.

Re:For us plebs...

in summary:

1. GE says two objects can cause a wobble in each other's axes due to gravity
2. Measurement of this wobble wasn't possible earlier
3. With this star system, since they are massive and pulsate, and that they are aligned in a manner that makes a measurement possible, astronomers took the plunge
4. Prof...proved.

Re:For us plebs...

Now THAT is a summary

Actually I recommend reading the article. It's short, understandable, and contains other cool facts about these neutron stars.

Also, as for that last "proved" bit, the article ends with:

"It's not quite right to say that we have now 'proven' General Relativity," Breton said. "However, so far, Einstein's theory has passed all the tests that have been conducted, including ours."

Laws and Theories

Law doesn't mean "confirmed theory", but is rather an element of a theory, typically characterised by its simplicity.

Consider, as examples, Newton's laws of motion, or the laws of thermodynamics. Newton's theory of motion is deduced from his laws; the conventional theory of thermodynamics, likewise.

I say this because there are plenty of non-scientists who deliberately attempt to exploit confusion induced by popular use of the terms "law" and "theory" so as to imply that scientific theories, notably the theory of evolution, are held tentatively.

Re:It's a shame really

Some time ago, I took a "History of Science" course. My memory is fuzzy around the dates, but originally, anything in science was granted the term "law". IIRC, "Caloric Theory" which was superseded by the theory of heat and thermodynamics was originally called a "law".

Around the 1700's, it was decided to call all new science a "Theory". In deference to previous conventions, the things still held over previously known as laws retained the name. Hence the apparent difference between the two terms.

hypothesis - 1 of 4 scientific terms

The word you are searching for is hypothesis.

There are 4 terms that need to be understood in the realm of science - hypothesis, theory, law & fact. They are all separate & distinct, except for the only progression that occurs - hypothesis => theory.

A fact is what has been carefully observed.
A law describes that observation.
A hypothesis is a proposal intended to explain that observation.
A theory seeks to explain that observation & has been confirmed by considerable evidence and has endured all attempts to disprove it.

example:

Fact
Objects fall at the same rate regardless of mass.

Law
http://www.glenbrook.k12.il.us/GBSSCI/PHYS/Class/circles/u6l3c1.gif [k12.il.us]

Hypothesis => Theory
Mass causes a curvature of spacetime which creates the effect of gravity.

Re:hypothesis - 1 of 4 scientific terms

The parent is not quite right.

An observation is some type of measurement. We could call this a fact if we like, but observation is better because is acknowledges the role of the observer in a way that "fact" does not.

A law is some invariance across multiple observations. See, for instance, Kepler's laws. (They do not, as the parent says, "describe" observations, but rather they postulate invariant aspects of planetary motion)

A hypothesis is a testable prediction based on naturalistic explanation of lawful behavior, typically of smaller scope than a theory and untested or weakly tested. Theories can also lead to hypotheses, through logical implication (ie, "my theory predicts that X, therefore I hypothesize X will occur in this experiment")

A theory is a unified, parsimonious, testable, naturalistic explanation for entire sets of laws. For instance, Newton's theory of mechanics explained all of Kepler's laws of planetary motion, and lawful behavior on earth as well.

Observation: These objects that I have dropped all appear to fall at the same rate regardless of mass, within measurement error

Law: All objects fall at the same rate regardless of mass

Hypothesis and theory Newton's theory of mechanics, or Einstein's theory of relativity

Re:And yet...

Einstein has yet to prove why hot dogs and hot dog buns come in inequal quantities.

      I guess relativity explains that again. It depends on your country. In my country, you get 8 buns in a package and 8 sausages in a package. However my country is probably closer to the equator than yours, therefore our frame of reference is a lot faster than yours. Therefore the parity increases as a function of velocity. I would probably have to weight the buns and sausages to figure out any discrepancies in mass, but presumably the optimum is reached asymptotically when approaching the speed of light.

Re:Relativity vs. Quantum

My understanding is that relativity has been directly observed several times, whereas quantum theory is still just based on the interpretation of a series of controlled laboratory experiments, which mostly amounts to sifting through the wreckage of a high-energy collision and trying to derive the original state from the leftover pieces.

Oh, just based on a series of controlled laboratory experiments. Unlike relativity??

I have no idea what "directly observed" means, but quantum mechanical behavior is no less directly observed than relativistic behavior. In fact, it is far better studied, since atomic physics is more accessible to experiments than relativistic physics. And it by no means is limited to high energy colliders (which is where you tend to see relativistic effects the most, by the way); atomic spectra, basically all of chemistry, condensed matter and material science, lasers, etc. all depend on quantum physics. Indeed, the quantum theory of electrodynamics is the most precisely verified theory in the history of physics; some of its predictions (like the electron g factor) are accurate to something like 12 decimal places when compared to experiments.

Isn't it about time to abandon the concept of the graviton and just accept that gravity is not a fundamental force, but is simply the observed effect of the curvature of spacetime due to the presence of matter and energy?

If you accept that matter is described by quantum mechanics, then general relativity is wrong, because you can't consistently couple a classical field to a quantum source. (Consider what happens when you want to describe the gravitational field of matter which exists in a quantum superposition of states.) Believe me, if it were that easy to produce a theory of gravity which is consistent with what we know about matter, people wouldn't have been searching for 50+ years for a theory of quantum gravity.

Once you accept that gravity needs to be quantized, then you are inevitably led to something like a graviton: it's what you get when you quantize the linearized approximation to general relativity, and is actually more general than that: any field which couples to stress-energy (which is the source of gravity in general relativity) is described by a rank-2 tensor, which in quantum mechanics means a spin-2 particle (graviton). A theory of quantum gravity won't have gravitons as truly fundamental — the perturbative theory of gravitons is inconsistent — but any such theory (e.g., string theory, loop quantum gravity) will necessarily have graviton-like behavior as a low energy limit, assuming that it also has a relativistic theory of gravity (like general relativity) as a classical limit. That is not inconsistent with GR's description of gravity as curved spacetime: that's the classical behavior of a graviton-like field, although different theories recover that limit in different ways. (String theory has strings which vibrate in graviton-like ways which are observationally indistinguishable from spacetime curvature; other theories try to quantize geometry directly.)

Re:Relativity vs. Quantum

My understanding is that relativity has been directly observed several times, whereas quantum theory is still just based on the interpretation of a series of controlled laboratory experiments, which mostly amounts to sifting through the wreckage of a high-energy collision and trying to derive the original state from the leftover pieces.

Nope. Quantum mechanics is vastly, overwhelmingly, massively tested. Compared to general relativity, quantum mechanics is easy to test in the lab, and there are many many many experimental validations of it

And general relativity, also, is getting to be well tested.

Both theories have passed all the tests that they have been put to.

The problem is: quantum mechanics becomes important for things that are very small. General relativity becomes important for objects with strong gravity. The only range where you can test both of them together is if you can find objects that are both extremely small, and have extremely high gravity. Unfortunately, that realm is outside the experimental range of any experiments, now or anytime in the forseeable future.